Blinded Clinical Trial
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A Blinded Clinical Trial is a clinical trial that is a blinded experiment (which withholds any information which may influence the participants until after the trial is completed).
- Context:
- It can aim to avoid observer bias, confirmation bias, placebo effect, and/or other sources of biases.
- It can range from being a Single-Blinded Clinical Trial to being a Double-Blinded Clinical Trial.
- …
- Example(s):
- a Single-Blinded Clinical Trial such as:
- a Double-Blinded Clinical Trial such as:
- …
- Counter-Example(s):
- See: Unblinding Clinical Trial Task, Clinical Trial Design, Experiment, Bias, Observer-Expectancy Effect, Observer Bias, Confirmation Bias, Clinical Protocol, Pain Medication, Antidepressants, Consolidated Standards of Reporting Trials, Scientific Method.
References
2021a
- (Wikipedia, 2021) ⇒ https://en.wikipedia.org/wiki/Blinded_experiment Retrieved:2021-11-21.
- In a blind or blinded experiment, information which may influence the participants of the experiment is withheld until after the experiment is complete. Good blinding can reduce or eliminate experimental biases that arise from a participants' expectations, observer's effect on the participants, observer bias, confirmation bias, and other sources. A blind can be imposed on any participant of an experiment, including subjects, researchers, technicians, data analysts, and evaluators. In some cases, while blinding would be useful, it is impossible or unethical. For example, it is not possible to blind a patient to their treatment in a physical therapy intervention. A good clinical protocol ensures that blinding is as effective as possible within ethical and practical constraints.
During the course of an experiment, a participant becomes unblinded if they deduce or otherwise obtain information that has been masked to them. For example, a patient who experiences a side effect may correctly guess their treatment, becoming unblinded. Unblinding is common in blinded experiments, particularly in pharmacological trials. In particular, trials on pain medication and antidepressants are poorly blinded. Unblinding that occurs before the conclusion of a study is a source of experimental error, as the bias that was eliminated by blinding is re-introduced. The CONSORT reporting guidelines recommend that all studies assess and report unblinding. In practice, very few studies do so.[1]
Blinding is an important tool of the scientific method, and is used in many fields of research. In some fields, such as medicine, it is considered essential. In clinical research, a trial that is not a blinded trial is called an open trial.
- In a blind or blinded experiment, information which may influence the participants of the experiment is withheld until after the experiment is complete. Good blinding can reduce or eliminate experimental biases that arise from a participants' expectations, observer's effect on the participants, observer bias, confirmation bias, and other sources. A blind can be imposed on any participant of an experiment, including subjects, researchers, technicians, data analysts, and evaluators. In some cases, while blinding would be useful, it is impossible or unethical. For example, it is not possible to blind a patient to their treatment in a physical therapy intervention. A good clinical protocol ensures that blinding is as effective as possible within ethical and practical constraints.
- ↑ Bello, Segun; Moustgaard, Helene; Hróbjartsson, Asbjørn (October 2014). “The risk of unblinding was infrequently and incompletely reported in 300 randomized clinical trial publications". Journal of Clinical Epidemiology. 67 (10): 1059–1069. doi:10.1016/j.jclinepi.2014.05.007. ISSN 1878-5921. PMID 24973822
2021b
- (Wikipedia, 2021) ⇒ https://en.wikipedia.org/wiki/Glossary_of_clinical_research Retrieved:2021-11-21.
- QUOTE: Blinded study
- A type of study in which the patients (single-blinded) or the patients and their doctors (double-blinded) do not know which drug or treatment is being given. The opposite of a blinded study is an open label study. (NCI)
- QUOTE: Blinded study
2021c
- (NIA/NIH, 2021) ⇒ https://www.nia.nih.gov/research/dgcg/nia-glossary-clinical-research-terms Retrieved:2021-11-21.
- QUOTE: Masking/Blinding – A procedure in which the investigator administering the assessments and intervention as well as the participants in a clinical trial are kept unaware of the treatment assignment(s). Single blinding usually refers to the study participant(s) being unaware, and double blinding usually refers to the study participant(s) and any of the following being unaware of the treatment assignment(s): investigator(s), monitor, and data analyst(s).
2021d
- (ClinicalTrials.gov, 2021) ⇒ https://www.clinicaltrials.gov/ct2/about-studies/glossary Retrieved:2021-11-21.
- QUOTE: Masking
- A clinical trial design strategy in which one or more parties involved in the trial, such as the investigator or participants, do not know which participants have been assigned which interventions. Types of masking include: open label, single blind masking, and double-blind masking.
- QUOTE: Masking
2021e
- (Novartis, 2021) ⇒ https://www.novartis.com/clinicaltrials/glossary-clinical-trial-terms Retrieved:2021-11-21.
- QUOTE: Blinding
- A type of clinical trial design in which one or more parties involved with the trial, such as the research team or participant, do not know which treatments have been assigned to which participants. See Double-blind and Single-blind below.
- QUOTE: Blinding
2021f
- (NCI, 2021) ⇒ https://www.cancer.gov/publications/dictionaries/cancer-terms/def/blinded-study Retrieved:2021-11-21.
- QUOTE: blinded study
- A type of study in which the patients (single-blinded) or the patients and their doctors (double-blinded) do not know which drug or treatment is being given. The opposite of a blinded study is an open label study.
- QUOTE: blinded study
2021g
- (MedicineNet, 2021) ⇒ https://www.medicinenet.com/blinded_study/definition.htm Retrieved:2021-11-21.
- QUOTE: Blinded study: A study done in such a way that the patients or subjects do not know (is blinded as to) what treatment they are receiving to ensure that the results are not affected by a placebo effect (the power of suggestion).
2008
- (Upton & Cook, 2008) ⇒ Graham Upton, and Ian Cook. (2008). “A Dictionary of Statistics, 2nd edition revised." Oxford University Press. ISBN:0199541450
- QUOTE: ... Blinding: A method of avoiding bias in the context of treating a disease. In a medical experiment, the comparison of treatments could be biased if either the patient, the doctor administering the treatment, or the data analyst knew which treatment was allocated to which patient. If the patient (or the doctor, or the data analyst) is unaware of which treatment is being given, then they are said to be ‘blind to' the treatment allocation process. If neither the patient nor the doctor is aware of the treatment allocation then the process is said to be a double-blind trial. In such an experiment, one treatment is often a dummy - for example, a pill of the same shape and flavor as the genuine pill, but with no active ingredients. This is called a placebo. In practice, there is often a placebo effect, in which the treated person shows a benefit despite the treatment theoretically having no effect. The effect is a reflection of the psychological benefit of believing that one is being given an effective treatment.